A Near-Field Gaussian Plume Inversion Flux Quantification Method, Applied to Unmanned Aerial Vehicle Sampling
A Near-Field Gaussian Plume Inversion Flux Quantification Method, Applied to Unmanned Aerial Vehicle Sampling
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DOI：
10.3390/atmos10070396
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发表时间：
2019-07-01
期刊：
影响因子：
2.9
通讯作者：
Bourn, Mark
中科院分区：
文献类型：
--
作者：
Shah, Adil;Allen, Grant;Bourn, Mark
需要准确量化点源的甲烷排放量，以便更好地量化排放量，用于具体部门的报告和清单验证。无人驾驶飞行器（UAV）作为一个平台，在源附近对羽流进行采样。本文介绍了一种近场高斯羽流反演（NGI）通量技术，适用于下风向采样的湍流羽流，通过拟合羽流模型测量的通量密度在三维空间。使用从八次无人机飞行中获得的样本数据对该方法进行了改进和测试，这些飞行测量了甲烷气体的受控释放。取样的最大高度为31米（即高于排放羽流的最大高度）。该方法适用于通量反演的羽流采样点源附近。为了测试该方法，一系列的随机游走抽样模拟被用来获得NGI的不确定性上限量化系统通量偏差由于一个有限的空间采样范围典型的短时间小型无人机飞行（小于30分钟）。NGI方法的开发使其未来能够用于量化点源的甲烷排放，促进未来对特定源类型和源区排放的评估。这使得可以使用顺风无人机采样来推导基于大气测量的通量，以进行相对快速的通量分析，而无需进入难以到达的区域。
The accurate quantification of methane emissions from point sources is required to better quantify emissions for sector-specific reporting and inventory validation. An unmanned aerial vehicle (UAV) serves as a platform to sample plumes near to source. This paper describes a near-field Gaussian plume inversion (NGI) flux technique, adapted for downwind sampling of turbulent plumes, by fitting a plume model to measured flux density in three spatial dimensions. The method was refined and tested using sample data acquired from eight UAV flights, which measured a controlled release of methane gas. Sampling was conducted to a maximum height of 31 m (i.e. above the maximum height of the emission plumes). The method applies a flux inversion to plumes sampled near point sources. To test the method, a series of random walk sampling simulations were used to derive an NGI upper uncertainty bound by quantifying systematic flux bias due to a limited spatial sampling extent typical for short-duration small UAV flights (less than 30 min). The development of the NGI method enables its future use to quantify methane emissions for point sources, facilitating future assessments of emissions from specific source-types and source areas. This allows for atmospheric measurement-based fluxes to be derived using downwind UAV sampling for relatively rapid flux analysis, without the need for access to difficult-to-reach areas.